Fluid pressure operated mechanism for circuit breakers



-Jan. 12, 1943.

H. S'ILEGELITZ ETAL FLUID PRESSURE OPERATED MECHANISM FOR CIRCUITBREAKERS Original Filed Feb. 26, 19:58

Inventor's: Hans .Stegelitz,

Wilhelm Schr ein W 'MMZ Their Attorney.

Patented Jan. 12, 1943 UNITED STATES PATENT OFFICE FLUID PRESSURE;OPERATED MECHANISM FOR CIRCUIT BREAKERS Hans Stegelitz,Berlin-Johannisthal, and Wilhelm Schreiner, Berlin-Nieder-Schonhausen,

Ger-

many; vested in the Alien Property Custodian 4 Claims.

Our invention relates to fluid pressure operated mechanisms, such as,for example, pneumatically actuated mechanisms for an electric circuitbreaker operable between open and closed circuit positions.

It has been recognized that the operating mechanism for closing a largecapacity electric circuit breaker, for example, should include asocalled seal for automatically insuring continuation of the operatingimpulse throughout substantially the entire closing stroke of thebreaker, and for discontinuing the impulse substantially at that point.Burning of the breaker contacts due to incomplete closure is thereforeprecluded and the usual trip-free feature assures short circuitprotection. Methods heretofore used have generally included electricrelays and auxiliary circuits which have not always workedsatisfactorily and which often complicate the operating mechanism.

The principal object of our invention is the provision of an improvedfluid-operated mechanism wherein an actuating impulse once initiated isautomatically carried through to completion of the circuit closingoperation and then discontinued.

This application is a division of our application Serial No. 192,804,filed February 26, 1938, for Fluid pressure operated mechanism, nowPatent No. 2,281,337.

Our invention will be more fully set forth in the following descriptionreferring to the accompanying drawing, and the features of novelty whichcharacterize our invention will be pointed out with particularity in theclaims annexed to and forming a part of this specification.

Referring to the drawing, the single figure thereof is a partlydiagrammatic layout of circuit breaker operating means embodying thepresent invention including a pneumatic seal for carrying through thebreaker actuating impulse.

The pneumatic circuit breaker operating system illustrated by way ofexample comprises a suitable source of fluid pressure, such as a conduitI connected to a gas reservoir (not shown), means adapted to be actuatedby fluid pressure, such as a fluid motor of the piston type generallyindicated at 2, and a main valve 3 for controlling the fluid connection4 between the pressure source and the actuating piston.

As specifically illustrated, the fluid motor 2 comprises a piston 5reciprocally operable within a cylinder 6 which is connected at itslower part to the fluid connection 4. The piston 5, through its pistonrod 5', is operatively connected in any suitable manner to the movablecontact I of an electric circuit breaker, such as by a pivoted link 8and an insulating connecting rod 9. The circuit breaker, which isdiagrammatically illustrated, comprises terminal conductors Ill and IIwhich are connected respectively to the fixed contact structure I2 andthe movable rod contact I.

The circuit breaker, which may of course be of the trip-free type butwhich is shown as non-tripfree in the interest of simplicity, is shownlatched in the closed circuit position by a pivoted latch member I3arranged to be controlled by the usual tripping solenoid i i. Thebreaker is normally biased toward open position by the spring l5 so thatwhen the tripping solenoid I4 is actuated in response to an overhead ortripping impulse, the latch I3 is rotated clockwise against the bias ofits resetting spring l3 causing downward or circuit opening movement ofthe rod contact 1. In the open circuit position, the roller 8 of thebreaker lever -8 engages the upper end of the piston rod 5' so that aworking stroke of the piston in response to opening of valve 3 iseffective to cause counter-clockwise rotation of the lever 8 and closingmovement of the contact 1. As the contact "1 reaches closed circuitposition, the latch 13, under bias of its spring 13, snaps beneath theroller 8" carried by the lever 8 to latch and hold the breaker in closedposition.

For the purpose of sealing the pneumatic operating impulse acting on thepiston 5 when the valve 3 is first opened, we provide a pneumatic timedelay device for automatically effecting closure of the valve 3 onlyafter it has been held open by fluid pressure for a predeterminedperiod, 1. e., for the time required to complete the working stroke ofthe piston 5. This assures complete closing of the circuit .breaker andprecludes the possibility of damage to the breaker by arcing that mightresult if the operating impulse were prematurely checked.

Specifically, the valve 3 controlling communication between the pressuresource I and the fluid connection 4 is adapted to be actuated by a leverIt pivoted at I5 having suitable actuating means, such as a push-buttonshown at IT. The lever I6 can be adjustably related to the valve stem I8of the valve 3 as indicated at [8. For the purpose of sealing open thevalve 3 after initial operation of the push-button, a diiierentialpiston 19 having two portions 20 and 2| is connected as at 22 to thelever [6. The differential piston operates Within a stepped-cylinderhousing 23, one end of which forms a cylinder for the piston portion 20connected at 24 through the connection 4' to the main fluid connection4. The other part of the housing forms a cylinder for the large piston2| that is in communication at 25 with the connection 4' through a timedelay device 26. The device 26 may comprise simply a fluid reservoir,the entrance of which at 21 can be suitably restricted with reference toan adjustable escape at 28, so that fluid pressure may build up in thecylinder of the piston 2i only after a predetermined time.

The operation of the pneumatic operating system will now be clear fromthe above description. When the push-button I1 is operated to causeinitial opening of the valve 3, the diiferential piston 2Q2l is alsomoved toward the left. As the gas under pressure enters the fluid motor2 by way of the connection 4, it also by way of connection 4' acts uponthe piston 20 of the dif ierential piston to hold it and the lever l6 soas to seal the valve 3 in open position. When, however, the fluidpressure transmitted through the time delay device 26 builds upsufilciently at the working face of the differential piston portion 21,the lever i and hence the valve 3 under influence of fluid pressure, isreturned to the initial position shown. The main valve 3 is now closedand held closed by the source pressure and the fluid motor in themeantime has received fluid pressure for e, suflicient period to assurecomplete closing of the breaker.

It should be understood that our invention is not limited to specificdetails of construction and arrangement thereof herein illustrated, andthat changes and modifications may occur to one skilled in the artwithout departing from the spirit of our invention.

, What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. Circuit breaker fluid operated actuating mechanism comprising asource of pressure, means adapted to be actuated by fluid pressure forclosing said circuit breaker, a valve for controlling a fluid connectionbetween said source and means, means for initiating the opening of saidvalve, an auxiliary pressure responsive device in communication withsaid connection for holding said valve in open position, a second fluidresponsive device having a larger effective pressure area for closingsaid valve when fluid pressure in said connection is transmittedthereto, and a fluid reservoir between said connection and said seconddevice for introducing a time delay in the operation of said device forassuring complete closure of said circuit breaker.

2. Circuit breaker operating mechanism of the pneumatic type comprisinga source of gas pressure, a piston arranged to be actuated by saidpressure for closing the circuit breaker, a valve for controlling a gasconnection between said source and piston, means for initiating theopening of said Valve, 2. difierential piston, the small diameterportion of which is in communication with said gas connection, meansoperatively connecting said valve and differential piston, and a gasreservoir disposed between said gas connection and the large diameterportion of said differential piston, said reservoir having mean forintroducing a, time delay in the building up of fluid pressure at saidlarge diameter portion for delayin the closing of said valve andassuring complete closing of said circuit breaker.

3. Circuit breaker operating mechanism of the pneumatic type comprisinga source of gas pressure, a piston arranged to be actuated by saidpressure for closing the circuit breaker, a valve for controlling a gasconnection between said source and piston, a member arranged to engageand open said valve, and time delay means for holding said member in thevalve-open position for a predetermined time for assuring completeclosing of said circuit breaker comprising a differential pistonconnected to said member, means for admitting gas under pressure fromsaid connection directly to the small diameter portion of saiddifferential piston, a gas reservoir for receiving gas under pressurefrom said connection and means for connecting said reservoir to thelarge diameter portion of said piston, said reservoir having restrictedpressure-transmitting openings so that there is a predetermined timedelay in the build-up of pressure at said large diameter portion tendingto return the differential piston and said member to the valve-closedposition.

4. A circuit breaker fluid operated actuating mechanism comprising asource of fluid pressure, a fluid motor adapted to be actuated by fluidpressure for closing said circuit breaker, a valve for controlling thefluid connection between said source and motor, a push button controlfor causing opening of said valve, said control being normally biasedtoward the valve-closed position, an auxiliary pressure responsivedevice including a differential piston adapted to be actuated to oneposition by fluid pressure from said source for maintaining open saidpush button control substantially throughout the circuit closing periodof operation of said motor, and a fluid connection includin a pneumatictime-delay device for connecting said source to said differential pistonfor actuating it to another position for causing closing of said valve.

HANS STEGELITZ. WILHELM SCHREINER.

